Location determination in sensor networks using time-window algorithm

Abstract

A network system and a method of determining a location of a transmitter are described. The method includes reading a signal strength of a signal transmitted by the transmitter by each of a plurality of receivers, at each frequency in a plurality of frequencies, extracting phase information using an amplitude of the signal at each of the plurality of frequencies, and applying a transform (such as a Fourier Transform) to the signal in the frequency domain to obtain a representation of the signal in the time-domain. The method further includes applying a time window to the signal in the time-domain to eliminate reflected multipath signals that arrive to the respective receivers later than a line-of-sight signal to obtain a windowed signal in the time domain, and calculating a location of the transceiver using the windowed time domain signal.

1 . A method of determining a location of a transmitter, comprising:
 reading a signal strength of a signal transmitted by the transmitter by each of a plurality of receivers, at each frequency in a plurality of frequencies;   extracting phase information using an amplitude of the signal at each of the plurality of frequencies;   applying a transform to the signal in the frequency domain to obtain a representation of the signal in the time domain;   applying a time window to the signal in the time domain to eliminate reflected multipath signals that arrive to the respective receivers later than a line-of-sight signal to obtain a windowed time domain signal; and   calculating a location of the transmitter using the windowed time domain signal.   
   
   
       2 . The method of  claim 1 , wherein calculating the location of the transmitter using the windowed time domain signal comprises:
 applying an inverse transform to the windowed time domain signal to return to a signal in the frequency domain; and   performing a multilateration procedure on the signal in the frequency domain to determine the location of the transmitter.   
   
   
       3 . The method of  claim 2 , wherein the applying of the inverse transform comprises applying an inverse Fourier Transform to the windowed time domain signal. 
   
   
       4 . The method of  claim 1 , wherein the applying of the transform comprises applying a Fourier Transform to the signal. 
   
   
       5 . A network of receivers, comprising:
 a plurality of receivers, each receiver being configured to receive a signal from a transmitter; and   a command and control center in communication with the plurality of receivers, the command and control center being configured to apply a time-window algorithm to the signal received by the receivers to determine the location of the transmitter;   wherein the time window algorithm comprises
 determining a signal strength of the signal by each of the plurality of receivers at each frequency in a plurality of frequencies; 
 extracting phase information using amplitude of the signal at each of the plurality of frequencies; 
 applying a transform to the signal in the frequency domain to obtain a representation of the signal in the time domain; 
 applying a time window to the representation of the signal in the time domain to eliminate reflected multipath signals that arrive later than a line-of-sight signal to obtain a windowed time domain signal; and 
 calculating a location of the transmitter using the windowed time domain signal. 
   
   
   
       6 . The network of transceivers according to  claim 5 , wherein the calculating a location of the transmitter using the windowed time domain signal comprises:
 applying an inverse transform to the windowed time domain signal to obtain a representation of the windowed time signal in the frequency domain; and   performing a multilateration procedure using the representation of the windowed time domain signal in the frequency domain to determine the location of the transmitter.   
   
   
       7 . The network of transceivers according to  claim 6 , wherein the inverse transform is an inverse Fourier Transform. 
   
   
       8 . The network of transceivers according to  claim 5 , wherein the transform is a Fourier Transform.